Climate Change

Sea Level Rise

Disappearing Island at French Frigate Shoals.

Over the course of the next century, global sea level is expected to rise due to thermal expansion of warming
oceans and melting ice caps and glaciers. The remote low-lying islands of the Northwestern Hawaiian Islands (NWHI)
may be particularly impacted as many of the islands rise no more than 2 meters (6.6 feet) above sea level. These
islands and atolls support the primary subpopulations of Hawaiian monk seals and provide critical habitat for
resting, molting and pupping necessary to survival.

The potential repercussions of reduced terrestrial habitat availability for NWHI monk seals are not fully
understood. It is likely seals will move to suitable higher elevation areas, which would increase seal densities
and may increase competition between seals resulting in negative population-level consequences.

Researchers continue to monitor for changes in sea surface heights and island acreage throughout the NWHI. This
continued monitoring will assist in planning mitigation strategies necessary for long term protection of the NWHI
and subsequently critical habitat for the Hawaiian monk seal.

Effects of El Niño

In temperate and polar regions where the vast majority of pinniped species are found, research has indicated seal
and sea lion populations have crashed following El Niño events due to increased sea-surface temperatures and the
resulting decline in prey availability. However, El Niño events are associated with cooler waters in Hawaii, and
studies have demonstrated improved body condition and survival of Hawaiian monk seal pups and juveniles following
El Niño years. These cooler waters can lead to improved diet or foraging efficiency of Hawaiian monk seals through
changes in prey availability, distribution, or quality. Impacts of oceanographic variability on monk seal foraging
continue to be evaluated.